Kalthur, Guruprasad

Context Women with obesity or polycystic ovary syndrome (PCOS) often require repeated ovulation induction (OI) due to ovulatory dysfunction and infertility. However, the cumulative effects of repeated stimulation on ovarian function and embryo development remain poorly understood. Aims The present study aimed to understand the consequences of repeated OI and/or repeated superovulation (SO) on preimplantation embryonic development in obese (high-fat diet-induced) and PCOS (high-fat diet and dehydroepiandrosterone-induced) mouse models. Methods Control (without any metabolic disorder), obese, and PCOS mice were divided into three experimental groups. The mice in one round of superovulation (SO1) were injected with 5 IU intraperitoneal (i.p.) injection of pregnant mare serum gonadotropin, followed by 10 IU of human chorionic gonadotropin 48 h later. In the repeated superovulation (SO3) group, mice were subjected to three rounds of superovulation with a gap of 9 days between each superovulation. Mice in the OI3 + SO3 group were administered with three doses of CC (50 mg/kg body weight, i.p., gap of 9 days between each CC injection), followed by three rounds of superovulation. Key results Both single and three rounds of superovulation resulted in decrease in primordial follicles and a moderate increase in atretic follicles in obese and PCOS mice. Reduction in the number of ovulated oocytes, increased rate of abnormal fertilization, decrease in blastocyst rate and elevated DNA damage in blastocysts were observed in in vitro fertilization-derived embryos. Conclusions These findings demonstrate compromised embryonic development following repeated ovarian stimulation. Implications The study highlights need for mild ovarian stimulation strategies in metabolically compromised patients undergoing infertility treatments.

The fallopian tubes are critical segments of the female reproductive tract and are essential for transporting gametes and embryos. It creates a conducive environment necessary for successful fertilization, early embryo development, and embryo transport. The cellular composition and function of the fallopian tube are tightly regulated by the sex hormones estradiol and progesterone. Therefore, any pathological/ metabolic condition or exposure to exogenous agents with the potential to alter endocrine levels can have a significant impact on fallopian tube function and health. This review summarizes the effects of medications, infections, pathological conditions, lifestyle choices, and environmental factors that can significantly impact the morphology, histology, cellularity, and functionality of the fallopian tube.

Abstract Polycystic ovarian syndrome (PCOS) is a complex health condition associated with metabolic disturbances and infertility. Recent data suggest that the prevalence of PCOS is increasing among women globally, although the etiology of these trends is undefined. Consequently, preclinical models that better reflect the biology of PCOS are urgently needed to facilitate research that can lead to the discovery of prevention strategies or improved management. The existing animal models have several limitations as they do not reflect all the PCOS features metabolically and/or phenotypically. Therefore, there is no clear consensus on the use of appropriate animal model and selection of the most appropriate PCOS-inducing agent. To that end, we have established a Swiss albino mouse model of PCOS based on 3 weeks of daily treatment with letrozole (50 μg/day; intraperitoneal) and dehydroepiandrosterone (DHEA, 6 mg/100 g body weight; subcutaneous) in 5-week-old female mice fed on normal or high-fat diet (HFD). Mice were regularly assessed for body weight, blood glucose, and estrous cycle. Three weeks after drug administration, mice were sacrificed and assessed for blood-based metabolic parameters as well as ovarian function. Our results indicate that DHEA combined with HFD produces changes mimicking those of clinical PCOS, including elevated serum testosterone and luteinizing hormone, dyslipidemia, poor ovarian microenvironment, and development of multiple ovarian cysts, recapitulating cardinal features of PCOS. In comparison, normal diet and/or letrozole produced fewer features of PCOS. The data from the experimental models presented here can improve our understanding of PCOS, a growing concern in women’s health.

e18055 Background: Entrectinib, a TRK kinase inhibitor, has been approved for the treatment of tissue agnostic rare tumors positive for TRK fusions. A very low frequency molecular subset of TRK fusion tumors dubbed as secretory carcinoma (SC) are characterized by organ-agnostic epithelial origin, ETV6-NTRK3 (EN) fusion and distinguishable secretory-type tumor cells. These tumors have been frequently miscategorized as acinic cell carcinoma or adenocarcinoma. A previous mouse study identified EGF dependent epithelial progenitors as putative cell-of-origin for SC. Methods: To test the role of EGFR signaling in EN mediated transformation and therapy resistance, we expressed EN, kinase-dead EN-K380M, and drug-resistant EN-G623R in human epithelial MCF10A cells with EGF-dependent primitive function and investigated their ability to grow in the presence and absence of EGF and/or entrectinib. To understand the significance of findings based on our model, we analyzed a total of 22 ‘rare’ patients from Mayo Clinic Tissue Registry and analyzed TCGA PanCan datasets. Results: We report herein that EGF signaling is essential for normal growth but dispensable during EN driven transformation. Our findings suggest that levels equivalent to circulating EGF (0.5-1ng/ml) is sufficient to drive 100% resistance to entrectinib in vitro. Three different strategies to blockade EGF/EGFR axis including depletion of EGF in culture system, genetic depletion of EGFR using shRNA as well as cetuximab antibody-based EGFR neutralization potentiated oncogene-addiction and hypersensitivity to entrectinib in our models. As predicted, models with G623R mutation in EN was refractory to entrectinib under all experimental conditions. Further omics analysis of TCGA PanCan suggested that EN and EGFR mutations are mutually exclusive and entrectinib-resistant G623R mutation were uncommon. Interestingly, nearly all EN tumors from Mayo Clinic Tissue Registry immunostained weakly or strongly for EGFR and showed perfect concordance with pEGFR suggesting pathway activation. Conclusions: Together, these findings raise an important question whether blockade of ‘wildtype’ EGFR signaling could improve medical intervention in SC patients presenting with wildtype EGFR and no drug-resistant mutation in entrectinib, by improving oncogene-addiction and attendant hypersensitization of transformed cells to entrectinib.